1. Field of the Invention
The present invention relates to a 3-wheel vehicle board, and more particularly, to a 3-wheel vehicle board which can stably maintain height of a handle bar and change a driving posture in various forms.
2. Description of the Related Art
A 3-wheel vehicle board has been developed differently from a two-wheel kick board. The 3-wheel vehicle board is used as sports equipment since a rider can run forwards even if he/she does not land on the ground to generate a running force. The 3-wheel vehicle board has a structure that a pair of rear tail arms are connected to the lower end of a front column where a handle bar is mounted, a steering wheel is installed in the lower end of the front column, and a rear wheel is installed in the rear end of each rear tail arm.
FIGS. 1 through 4 illustrate an example of the 3-wheel vehicle board. Referring to FIGS. 1 through 4, the 3-wheel vehicle board includes a handle bar 11 provided in the upper end thereof, a handle bar shaft 10 with the lower end of which a front wheel 51 is rotatably combined, a second hollow shaft 25 with which the handle bar shaft 10 is slidably combined, a first hollow shaft 20 with which the second hollow shaft 25 is rotatably combined, a locking/unlocking unit for fixing and releasing position of the handle bar shaft 10 with respect to the second hollow shaft 25, a fixing block 70 which is fixed to the lower end of the first hollow shaft 20, first and second rotatable links 31 and 32 with each one end of which each one end of the fixing block 70 is rotatably combined, a connection block 80 with each one end of which the respective middle portions of the first and second rotatable links 31 and 32 are rotatably combined, and with the middle portion of which the fixing block 70 is rotatably combined, first and second foothold links 41 and 42 which are rotatably combined with each one end of the first and second rotatable links 31 and 32 with a hinge pin 91 or 92 and on each one end of which each foothold 61 or 62 and each rear wheel 52 or 53 are provided, and a clamping unit which fixes the first and second foothold links 41 and 42 horizontally and vertically with respect to the first and second rotatable links 31 and 32.
Referring to FIGS. 1 and 4, the locking/unlocking unit includes an elastic plate 21 whose ends are spaced by a predetermined gap and then surround the outer circumferential surface of the second hollow shaft 25, and a locker 22 which tightens or releases both the ends of the elastic plate 21, in which the inner diameter of the second hollow shaft 25 is reduced by tightening the elastic plate 21 to thus fix the handle bar shaft 10. In order to change the inner diameter of the second hollow shaft 25, a slit 25a is formed perpendicularly from the upper end of the second hollow shaft 25. Referring to FIGS. 2 and 3, coupling holes are formed on the leading ends of the first and second foothold links 41 and 42, first and second locking holes 32a and 31b spaced by a predetermined angle with respect to rotational pins 91 and 92 are formed on the leading ends of the first and second rotatable links 31 and 32, and the first and second locking holes 32a and 31b are selectively coupled to the coupling holes with locking pins 100. As shown in FIGS. 2 and 3, the first and second locking holes in the first and second rotatable links 31 and 32 are formed identically, and thus only visible components in the drawings are assigned with reference numerals. Referring to FIG. 3, an elastic wire 101 curved in the form of an arc is further provided in order to couple both the ends of the locking pin 100 and surround the first and second rotatable links 31 and 32 and the first and second foothold links 41 and 42. The locking pin 100 is surrounded by the elastic wire 101 to thereby prevent separation from the locking hole.
However, the 3-wheel vehicle board has the following problems.
Firstly, since the handle bar 11 is formed in the form of a straight line, and is combined vertically with the handle bar shaft 10, the 3-wheel vehicle board is difficult to adapt itself to the physical conditions or driving posture of a user.
Secondly, since the handle bar 11 is fixed by the lateral surface pressure of the locker 22 after the height of the handle bar 11 has been adjusted, the 3-wheel vehicle board is vulnerable to the vertical pressure. As a result, the height adjusted handle bar can be moved to accordingly cause a safety accident.
Thirdly, since the first and second rotatable links 31 and 32 and the first and second foothold links 41 and 42 are combined with the locking pins 100 further including the elastic wires 101, it is burdensome to assemble and disassemble the components into and from the 3-wheel vehicle board, respectively.
Finally, since impacts are transferred to the handle bar 11 via the front wheel 51 from the ground, a sense of boarding goes bad during running.